In the user manual, be more specific about what snapshots include

Submitted by Jean-François Fortin Tam @jfft

Description

In the GNOME Boxes user help, there's a mention of snapshot as something that may help deal with breaking machines etc.

I think it would be interesting to go the extra mile on that topic and reassure the user that everything is preserved. VirtualBox's manual is pretty exhaustive regarding what the snapshots include (and thus it's pretty comforting). For example: https://www.virtualbox.org/manual/ch01.html#idp56573712